There are a number of methods in existence for the direct conversion of solar energy into electricity. One example is solar conversion by semiconductors via the direct photoexcitation of electrons from the valence band to the conduction band. Typical semiconductors include Silicon and Germanium wafers. An extension of this method to organic molecules such as Chlorophyll has also been made although the yields reported have always been very low, as reported by C. W. Tang and A. C. Albrecht, J. Chem. Phys., 63 953 (1975). Other semiconductors have been employed in electrochemical cells. By using TiO.sub.2, Fujishima and Honda have successfully split water into H.sub.2 and O.sub.2 using blue light. Another known example is the conversion of photons to electricity by the photon induced potential changes at metal electrodes inserted in a homogeneous solution such as the mixture of Fe.sup.2.sup.+ and thionine.
A basic difficulty with all the aforesaid devices and techniques is the low yield of energy out compared with the light energy put into the system. If solar energy is to be used at all, the conversion efficiency must be improved.